docs: def get_next_section_start_line(self, data):
          """Get the starting line number of next section.
          It will return -1 if no section was found.
          The section is a section key (e.g. 'Parameters') followed by underline
          (made by -), then the content
  
          :param data: a list of strings containing the docstring's lines
          :type data: list(str)
          :returns: the index of next section else -1
  
          """
          start = -1
          for i, line in enumerate(data):
              if start != -1:
                  # we found the key so check if this is the underline
                  if line.strip() and isin_alone(['-' * len(line.strip())], line):
                      break
                  else:
                      start = -1
              if isin_alone(self.opt.values(), line):
                  start = i
          return start